This section is intended to introduce various aspects of the art, which may be associated with exemplary embodiments of the present techniques. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present techniques. Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art.
The production of hydrocarbons, such as oil and gas, has been performed for numerous years. To produce these hydrocarbons, a production system may utilize various devices, such as sand screens and other tools, for specific tasks within a well. Typically, these devices are placed into a wellbore completed in either a cased-hole or open-hole completion. In cased-hole completions, a casing string is placed in the wellbore and perforations are made through the casing string into subterranean formations to provide a flow path for formation fluids, such as hydrocarbons, into the wellbore. Alternatively, in open-hole completions, a production string is positioned inside the wellbore without a casing string. The formation fluids flow through the annulus between the subsurface formation and the production string to enter the production string.
However, when producing hydrocarbons from some subterranean formations, it becomes more challenging because of the location of certain subterranean formations. For example, some subterranean formations are located in ultra-deep water, at depths that extend the reach of drilling operations, in high pressure/temperature reservoirs, in long intervals, in formations with high production rates, and at remote locations. As such, the location of the subterranean formation may present problems that increase the individual well cost dramatically. That is, the cost of accessing the subterranean formation may result in fewer wells being completed for an economical field development. Further, loss of sand control may result in sand production at surface, downhole equipment damage, reduced well productivity and/or loss of the well. Accordingly, well reliability and longevity become design considerations to avoid undesired production loss and expensive intervention or workovers for these wells.
Typically, sand control devices are utilized within a well to manage the production of solid material, such as sand. The sand control device may have slotted openings or may be wrapped by a screen. As an example, when producing formation fluids from subterranean formations located in deep water, it is possible to produce solid material along with the formation fluids because the formations are poorly consolidated or the formations are weakened by downhole stress due to wellbore excavation and formation fluid withdrawal. Accordingly, sand control devices, which are usually installed downhole across these formations to retain solid material, allow formation fluids to be produced without the solid materials above a certain size.
However, under the harsh environment in a wellbore, sand control devices are susceptible to damage due to high stress, erosion, plugging, compaction/subsidence, etc. As a result, sand control devices are generally utilized with other methods to manage the production of sand from the subterranean formation.
One of the most commonly used methods to control sand is a gravel pack. Gravel packing a well involves placing gravel or other particulate matter around a sand control device coupled to the production string. For instance, in an open-hole completion, a gravel pack is typically positioned between the wall of the wellbore and a sand screen that surrounds a perforated base pipe. Alternatively, in a cased-hole completion, a gravel pack is positioned between a perforated casing string and a sand screen that surrounds a perforated base pipe. Regardless of the completion type, formation fluids flow from the subterranean formation into the production string through the gravel pack and sand control device.
During gravel packing operations, inadvertent loss of a carrier fluid may form sand bridges within the interval to be gravel packed. For example, in a thick or inclined production interval, a poor distribution of gravel (i.e. incomplete packing of the interval resulting in voids in the gravel pack) may occur with a premature loss of liquid from the gravel slurry into the formation. This fluid loss may cause sand bridges to form in the annulus before the gravel pack has been completed. To address this problem, alternate flowpaths, such as shunt tubes, may be utilized to bypass sand bridges and distribute the gravel evenly through the intervals. For further details of such alternate flowpaths, see U.S. Pat. Nos. 4,945,991; 5,082,052; 5,113,935; 5,333,688; 5,515,915; 5,868,200; 5,890,533; 6,059,032; 6,588,506; and International Application Publication No. WO 2004/094784; which are incorporated herein by reference.
While the shunt tubes assist in forming the gravel pack, the use of shunt tubes may limit the methods of providing zonal isolation with gravel packs because the shunt tubes complicate the use of a packer in connection with sand control devices. For example, such an assembly requires that the flow path of the shunt tubes be un-interrupted when engaging a packer. If the shunt tubes are disposed exterior to the packer, they may be damaged when the packer expands or they may interfere with the proper operation of the packer. Shunt tubes in eccentric alignment with the well tool may require the packer to be in eccentric alignment, which makes the overall diameter of the well tool larger and non-uniform. Existing designs utilize a union type connection, a timed connection to align the multiple tubes, a jumper shunt tube connection between joint assemblies, or a cylindrical cover plate over the connection. These connections are expensive, time-consuming, and/or difficult to handle on the rig floor while making up and installing the production tubing string.
Concentric alternate flow paths utilizing smaller-diameter, round shunt tubes are preferable, but create other design difficulties. Concentric shunt tube designs are complicated by the need for highly precise alignment of the internal shunt tubes and the basepipe of the packer with the shunt tubes and basepipe of the sand control devices. If the shunt tubes are disposed external to the sand screen, the tubes are exposed to the harsh wellbore environment and are likely to be damaged during installation or operation. The high precision requirements to align the shunt tubes make manufacture and assembly of the well tools more costly and time consuming. Some devices have been developed to simplify this make-up, but are generally not effective.
Some examples of internal shunt devices are the subject of U.S. Patent Application Publication Nos. 2005/0082060, 2005/0061501, 2005/0028977, and 2004/0140089. These patent applications generally describe sand control devices having shunt tubes disposed between a basepipe and a sand screen, wherein the shunt tubes are in direct fluid communication with a crossover tool for distributing a gravel pack. They describe the use of a manifold region above the make-up connection and nozzles spaced intermittently along the shunt tubes. However, these devices are not effective for completions longer than about 3,500 feet.
Accordingly, the need exists for a method and apparatus that provides alternate flow paths for a variety of well tools, including, but not limited to sand control devices, sand screens, and packers to gravel pack different intervals within a well, and a system and method for efficiently coupling the well tools.
Other related material may be found in at least U.S. Pat. Nos. 5,476,143; 5,588,487; 5,934,376; 6,227,303; 6,298,916; 6,464,261; 6,516,882; 6,588,506; 6,749,023; 6,752,207; 6,789,624; 6,814,139; 6,817,410; 6,883,608; International Application Publication No. WO 2004/094769; U.S. Patent Application Publication No. 2004/0003922; U.S. Patent Application Publication No. 2005/0284643; U.S. Patent Application Publication No. 2005/0205269; and “Alternate Path Completions: A Critical Review and Lessons Learned From Case Histories With Recommended Practices for Deepwater Applications,” G. Hurst, et al. SPE Paper No. 86532-MS.